A plugin that extend Rainmeter functionality: Get apps volume and peak level, control apps volume and mute.Download:https://github.com/khanhas/AppVolumePlugin/releasesPARENT MEASURE
Option:IgnoreSystemSound(default = 1)System sound is Windows notification sound.Set to 0 to include System Sound. Set to 1 to skip System Sound.

Number value: Total number of apps. You can use this value to generate enough child measures and prevent out of range error.
String value: Current device name.

Index(default = 0)Index of app you want to get information and control. It has to be in range from 1 to number value of Parent measure.

AppNameSpecific name of app you want to get information and control. You need to include app name and its extension. Eg: Spotify.exe, AIMP.exeIf this option is not empty and Index is also set, it overrides Index option.

NumberType(default = volume)Value you want to return in number value of measure. Valid options are volume or peak.

StringType(default = filename)Value you want to return in string value of measure. Valid options are filename or filepath.

!CommandMeasure MeasureName "ChangeVolume x"Change the volume by *x*. You can use negative numbers to decrease volume.

!CommandMeasure MeasureName "Mute"Mute app.

!CommandMeasure MeasureName "UnMute"Unmute app.

!CommandMeasure MeasureName "ToggleMute"Toggle mute app.SECTION VARIABLES
Only available in Rainmeter version >= 4.1
An additional way to get app volume and peak by index or app name. DynamicVariables = 1 is required in where you use these variables.[ParentMeasureName:GetVolumeFromIndex(x)]
[ParentMeasureName:GetPeakFromIndex(x)]
[ParentMeasureName:GetFileNameFromIndex(x)]
[ParentMeasureName:GetFilePathFromIndex(x)]x is from 1 to number value of Parent measure.

[ParentMeasureName:GetVolumeFromAppName(name)]
[ParentMeasureName:GetPeakFromAppName(name)]name is name of app you want to get. You need to include app name and its extension.